Sound recording and reproducing instrument



W. CLIFYON AND). S. EWART. SOUND RECORDING AND REPRODUCING INSTRUMENT.

APPLICATION FILED JUNE 21. 1921.

1,42 5,944. Patented Aug- 15, 1922.

To all whom it may concern:

Be it known that we, WILLIAM ERNEST CLIFTON and J OHN STURTON EWART,subjects of the King of England, residing in Nottingham, England, haveinvented certain new and useful Improvements in Sound Recording andReproducing Instruments, of which the following is a specification.

This invention consists in improvements in or relating tosound-recording and soundreproducing instruments for use withgramophones and like machines. The type of instrument to which thepresent invention relates is that in which a flexible diaphragm iscarried in a casing, hereinafter referred to as the sound-box, and thediaphragm is firmly connected to one end of a lever or stylus-barpivotally mounted on the soundbox so that it can oscillate in a plane atright-angles to the diaphragm. The other end of the lever is formed toreceive a needle the point of Which serves either to record on a plasticbody vibrations imparted to thediaphragm or, in reproducing, the pointof the needle is oscillated by the record to transmit vibrations to thediaphragm. The object of the present invention is to provide means forarticulating the stylusbar to the sound-box .in an improved manner sothat in recording on a record surface the vibrations will bemoreaccurate and clear than heretofore and in reproducing the soundsproduced will be clearer, more pure in tone, and more free from noisescommonly known, inter alia, as jarring or .shocks or needle-scratchingthan is possible with known constructions of similar instruments.

According to the present invention the means for articulating astylus-bar comprise one or more spring blades each of which is connectedby its ends respectively to the sound-box casing and to the stylus-barat aposition intermediate in the length ofthe latter, and is so disposedthat its line or region of flexure is substantially in the plane of thediaphragm. In one form the spring blade or blades are themselvesparallel with,

or substantially in, the plane of the diaphragm.

Preferably, however, the blade or set of blades above described iscombined with a second blade or set disposed in a plane at right-anglesto the plane of the first blade or set and to that of the diaphragm. *In

Specification of Letters Patent. Application filed .Tune 21, 1921.

Patented Aug. 15, 1922. SeriaI No. 479,380. r

such a construction the stylus-bar is conveniently formed with alaterally-projecting abutment disposed adjacent to the rim of thesound-box casing and the two spring lades or sets of blades are sooperatively connected between the abutment and the sound-box casing thatthe lines or regions of flexure of all the blades are substantially inthe plane of the diaphragm.

ne preferred form of the invention will now be described with the aid ofthe accompanying drawings, in which lgure l is a front elevation of thestylusbar and its articulating means with the sound-box casing shown inchain lines;

Figure 2 is a perspective detail view of the1 articulating means on anenlarged scale; an

Figure 3 shows a modified form of soundbox and stylus-bar.

Like reference numerals indicate like parts in the two figures of thedrawings.

The stylus-bar 1 is, at a point intermediate in its length, formed withan abutment 2 adapted to lie substantially parallel with and in registerwith the edge of the sound ox casing, which latter is indicated at 3.The abutment 2 has an upturned extremity 4 and from the abutmentprojects what is virtually part of the stylus-bar in the form of aneedle-socket 5. The other end of the stylus-bar 6 is rigidly connectedto the diaphragm.

A blade or strip 7, which is adapted to be secured by screws 8 to thesound-box casis connected with the abutment 2 by means of two springblades or strips 9 which are so' disposed in relation to that they willbe substantially in the plane of the latter. Other spring blades 10, atright-angles to the blades 9, are operatively connected between theupturned lug 4 and a lug 11 forming part of the plate 7 and normallyparallel with the lug 4. The dimension and disposition of the blades 10is such that their normal region of flexure is substantially in theplane of the diaphragm. It will be appreciated also that the normalregion of 'flexure of the blades 9 is in the same plane so that bothsets of blades are normally flexed in substantially the same plane whichis that of the diaphragm. i

The needle-socket 5 is so disposed that a needle 12, secured therein bythe usual screw the diaphragm l3,'is disposed substantially centrally inthe plane of the diaphragm and the blades 9.

It is found with this construction that end pressure on the needle 12 isreceived as end thrust on the blades 9 normally causing no flexure ofthe latter. Should, however, comparatively violent end shocks beimparted to the needle such as, and sufficient, to cause fiexure of theblades .9, the blades 10 tend to resist and to take up such undueshocks. The normal sound vibrations which oscillate the stylus-bar in aplane at right-angles to that of the diaphragm are permitted readily bythe flexing of both sets of spring. blades.

In Figure 3 the sound-box 3 is shown as operating with its circular faceopposed to or facing the record surface 14 as distinct from the form ofsound-box illustrated in Figure 1 in which the circular-face of thesound-box is in a planeat right-angles to the surface of the record. InFigure 3 the stylus-bar 1 is formed with an equivalent abutment 2 andupturned extremity 4 but the needle socket 5 is now substantially inprolongation of the abutment 2. As in the previously describedconstruction, two sets of spring blades 9 and 10 are provided toarticulate the stylus-bar to the plate 7 but the needle will now besubstantially in the plane of the blades 10 instead of that of theblades 9 as abov described.

With the construction shown in Figure 3, it is found that all tendencywhich the sound-box of Figure 1 has to be oscillated about an axisapproximately in the plane of the sound-box, is now eliminated, with theresult that still further improvements in tone and clarity of the soundsproduced is obtained. Th tone-arm 15 will conveniently be formed as anintegral portion of, orv

rigidly secured to, the sound-box casing.

As both sets of blades are firmly secured in the parts to which they areattached, for example by silver-soldering or other preferred means,extraneous noise such as is often apparent where pivot-pins or likedevices are employed for articulating the stylus-bar is eliminated. Suchnoises accrue, amongst other reasons, from the friction of theneedle-point on the record and with pivot-pin or like articulation ofthe stylus-bar slight movement of the pivots from this cause andunevennesses in the surface of the record are transmitted to thediaphragm a jarring or scratching noise. Such noises are eliminated bythe present construction and the pure tones produced by the desiredsound vibration of the diaphragm remain substantially unimpaired byextraneous and objectionable noises.

If desired, only one of the sets of spring blades may be employed as thesole means of articulation of the stylus-bar, conveniently a set such as9. Insuch a form it is essential that the region of flexure of theblades should be in, or substantially in, the plane of the diaphragm.

What we claim as our invention and dcsire to secure by Letters Patentis 1. Means for articulating a stylus bar to the casing of a sound boxof the type described, said means comprising at least two spring bladeswhereof one blade is disposed in a plane at right angles to the plane ofthe other blade and one of the blades is arranged in or substantially inthe plane of the diaphragm, an operative connection between one end ofeach blade and the sound box casing and another operative connectionbetween the other end of each blade and the stylus bar at a positionintermediate in the length of the latter.

2. Means for articulating a stylus bar to the casing of a sound box ofthe type 'described, said means comprising two sets of spring bladeswhereof the blades of one set are disposed in a plane at right angles tothe plane containing the blades of the other set and the blades of oneset are arranged in or-substantially in the plane of the diaphragm, anoperative connection between one end of each blade and the sound boxcasing and another operative connection between the other end of eachblade and the stylus bar at a position intermediate in the length of thelatter.

3. Means for articulating a stylus bar to the casing of a sound box ofthe type described, said means comprising at least two spring bladeswhereof one blade is disposed in a plane at right angles to the plane oftheother blade with one ofthe blades arranged in or substantially in theplane of the diaphragm, and the two blades are so arranged that eachcrosses the other in a plane which bisects or approximately bisects it,an operative connectlon between one end of each blade and the sound-boxcasing and another operative connection between the other end of eachblade and the stylus bar at a position intermediate in the length of thelatter.

4;. Means for articulating a'stylus bar to the casing of a sound box ofthe type described, said means comprising at least two spring bladeswhereof one blade is disposed in a plane at right angles tothe plane ofthe other blade, a stylus bar formed near its outer end with a laterallyprojecting abutment disposed adjacent to the rim of the sound boxcasing, an operative connection between one end of each of the bladesand the sound box casing, and another operative connection between theother end of each' blade and said abutment such that the two bladescross one another at aposition which is substantially in the plane ofthe diaphragm.

5. Means for articulating a stylus bar formed with a needle socket tothe casing of a sound box of the type" described, said means comprisingat least two blades whereof one blade is disposed in a plane at rightangles to the plane of the other blade, an operative connection betweenone end of each blade and the sound box casing, and another operativeconnection between the other end of each blade and the stylus bar,

said operative connections being such that one of the blades iscontained in or approximately in a plane which will contain also theaxis of the needle when in said needle socket.

6. Means for articulating a stylus bar formed with a needle socket tothe casing of a sound box of the type described, said means comprisingat-least two spring blades whereof-one blade is disposed in aplane atright angles to the plane of the other blade, an operative connectionbetween one end of each blade and the sound box casing, and anotheroperative connection between the other end of each blade and the stylusbar, the said operative connections being such that one of the blades iscontained in or approximately in a plane which will contain also theaxis of the needle. when in said needle socket, said plane being atright angles or approximately at right angles to the plane of thediaphragm.

7. Means for articulating a stylus bar having a needle socket to thecasing of a sound box of the type described, said means comprising twopairs of spring blades whereof the blades of one pair are disposed -in aplane'at right angles to a plane containing the other pair, anintermediate member adapted to be secured to the sound box casing, anoperative connection between one end of each of the blades and thestylusbar, and another operative connection between the other end.ofeach of the blades and said intermediate member, said operatermediatemember, said when in said needle tive connections being such that eachpair of the blades crosses the other pair at a position whichsubstantially bisects the blades of said other pair, and the plane ofone pair of blades is in or substantially in plane of the diaphragmwhereas the plane of the other pair of blades is in or substantially ina plane which will contain the axis of the needle when in said needlesocket.

8. Means for articulating a stylus bar having a needle socket to thecasing of a sound box of the type described, said means comprising twopairs of spring blades whereof the bladesof one pair are disposed in aplane at right angles to a plane containing the other pair, anintermediate member adapted to be secured to the sound box casing, anoperative connection between one end of each of the blades and thestylus bar, and another operative connection between the other end ofeach of the blades and said inoperative connections being such that eachpair of the blades crbsses the other pair at a position whichsubstantially bisects the blades of said other pair, and the plane ofone pair of blades is in or substantially in the plane of the diaphragmwhereas the plane of the other pair of blades is in or substantially ina plane which will contain the axis of the needle socket, andis at rightangles or substantially at right angles to the plane of the diaphragm.

In testimony whereof we have signed our names tothis specification inthe presence of two subscribing witnesses.

\VILLIAM ERNEST CLIFTON.

JOHN STURTON EWART. lVitnesses:

CHAs. L. NORDON,

ALFRED HORNEB.

